Wait, is Zack looking right at us? Does he know he's a character in a TV show or not?

It is generally assumed in fiction that characters are completely unaware of the fact that they're in a fictional world with a "fourth wall" like a two-way mirror that we, the audience, are watching them through.

But sometimes the characters break the fourth wall by addressing the audience – like Deadpool or Frank Underwood – and becoming far too aware of their fictional existence. When you think about it long enough, it all gets a bit postmodern and scary. Are we real? Are we actually in the Matrix?

Advertisement - Continue Reading Below

Here are eight times when TV shows went totally bonkers and tore down the wall:

1. Doctor Who: The First Doctor wishes everyone a happy Christmas

Doctor Who has had many wibbly-wobbly brushes with the fourth wall over the decades. The first was in 'The Feast of Steven', when William Hartnell genuinely made a toast and wished everyone watching at home a merry Christmas, like it was an episode of Blue Peter or something.

Tom Baker's Fourth Doctor also spoke to the camera on various occasions. The funniest of these was during 'The Invasion of Time', when he said right to the camera: "Even the sonic screwdriver won't get me out of this one." Come on, Tom – stop mucking about.

It's not just in the old days, either. In classic episode 'Blink', David Tennant looks directly at the camera while telling the audience his video warning to Sally Sparrow: "Don't blink. Blink and you're dead. Don't turn your back. Don't look away. And don't blink. Good Luck." Stop terrifying us! Plus, there are bits in the episode where the Weeping Angels are visible on screen – and therefore observed somehow – but none of the characters are looking at them. We are. Argh.

Yes, House of Cards' Frank Underwood can talk to the camera. Even Lovejoy used to do that. They have nothing on Zack Morris. Not only does Zack repeatedly talk directly to the audience, but he can actually stop reality at will.

So, that raises the question: is Zack just a character? Or is he the narrator? Or is he an actor fooling everyone?

Is he a… god?

Then there was that time that Zack appeared as a guest on Late Night with Jimmy Fallon to promote his show Raising the Bar, explaining that Mark-Paul Gosselaar was just a stage name. This is trippier than an episode of Twin Peaks.

Advertisement - Continue Reading Below

3. The Red Dwarf boys met Craig Charles on the set of Coronation Street

Admittedly, this wasn't Red Dwarf's finest hour, but it did at least bring back the small rouge one after nearly a decade away.

In the Back to Earth serial, the boys finally found Earth, and discovered that they were actually just TV characters in a British sitcom called Red Dwarf on a channel called Dave. And so they went out of their way to seek out Lister's "actor" Craig Charles, at his current place of work – Coronation Street. The episode got more and more mental, as the boys met "Craig" and fellow Corrie stars Simon Gregson and Michelle Keegan. What the hell?

They even found a copy of the Back to Earth DVD in the shops, which ended up looking exactly the same as the real-world copy of it, for Cat's sake.

In the end all this was explained away as one big fantasy hallucinogenic world created by a form of despair squid, so it didn't actually happen. But by creating a world exactly the same as "our" Earth, Red Dwarf couldn't get more postmodern if it tried.

Supernatural also pulled off a similar move in the episode 'The French Mistake', when Sam and Dean land in an alternate reality where they're actually the actors Jared Padalecki and Jensen Ackles in a show called Supernatural. When they search for Castiel, they find Misha Collins. See, this is what happens when you run for over ten seasons.

4. The Fresh Prince of Bel-Air producers literally dragged Will Smith back to the show

We all remember how Will would often break the fourth wall by looking at the camera and goofing about, but the show's fifth season went totally doo-lally.

In the fourth season finale, Will decides to move back to Philadelphia. When the fifth season commenced, Will is forcibly abducted by network NBC executives in a van that reads 'NBC Star Retrieval' with the NBC logo. He is chucked in the van, driven back to Bel-Air, and the show just carries on like nothing happened.

In the next scene, Jazz asks who'll be playing Aunt Viv that season (referencing the change of actress in season 4), to which a suddenly 5-year-old Nicky tells him it'll be the same actress as the previous year. When Jazz asks why Nicky is 5 now when he was a toddler in the previous episode, Will just shrugs.

Also, in the fourth season finale, Will confronts a bully named Omar, who Will describes as "the dude who be spinning me over his head in the opening credits". There clearly came a point in the fourth season where the writers lost all grip of reality.

This was a subtle gag that showed that Scrubs didn't care how niche it was getting by the time it reached its eighth season.

After seven seasons, Scrubs was dropped from NBC, but ABC bought it the following year. Zach Braff's JD sort of references this without breaking the fourth wall, by pointing at the area of the screen in which the ABC logo would be seen by viewers at home and saying: "Ooh, that's new!"

The camera then flips around and it turns out that he was actually looking at the Janitor's new watch.

This joke didn't make any sense whatsoever when repeated on other channels or released on DVD, as the logo ain't there. And so JD looks really weird pointing in a really awkward manner.

During season 3, Chase used to refer to how he would remind Cameron that he loved her once a week. He said that he did this every Tuesday, which just so happened to be the day Fox aired new episodes of the show.

Then there was the time when Cuddy yelled at House about how he storms into her office "24 times a year", referencing how 24 episodes is the standard length of a TV season in the States.

Finally, there was the episode 'Frozen', in which Cuddy cuts off cable access to the room of a coma patient that House would frequently use. She tells him that he'll have to use the broadcast networks instead, to which he replies : "I'll be fine on Tuesdays." Again, Tuesdays was when House was on the telly.

7. Moonlighting ended with the characters being told the show was axed

The 1980s romantic crime comedy starring Bruce Willis and Cybill Shepherd would often play around with the fourth wall, to the point where the building probably needed to be demolished.

But the craziest moment of all was in its final ever episode, which sees David and Maddie discovering that Moonlighting has been cancelled, and shows their office/set being dismantled by studio staff.

They then confront a producer who tells them that "romance is a fragile thing" and that theirs is over. Well, that's one way to end a show after five years.

8. Two and a Half Men ended with its creator referencing his beef with Charlie Sheen

The sitcom had been limping along for many years, especially after the departure of Charlie Sheen several seasons before. By the end, it was a shell of a show that should have been put out of its misery long before. It lasted longer than Friends. Let that sink in.

When it did finally end, creator Chuck Lorre (the man behind The Big Bang Theory) decided to just say "f**k it" and went all meta, like that's totally fine. To save you from having to watch it, the final scene saw 'Charlie' (obviously not really him) return to the house, only for him to be killed by a piano falling from the sky. And then the camera pans out to Lorre in a director's chair saying Sheen's real-world catchphrase "winning", before a piano drops on him too.

It's like he knew just how bad this show had become and didn't care about any kind of fan service. Like two fingers proudly held aloft towards all the idiots who bothered watching in the first place.